const _SINGLETON_ = Symbol('_SINGLETON_')

class Singleton{
	constructor(){
		if(Singleton[_SINGLETON_]) return Singleton[_SINGLETON_];
		console.log('this is Singleton instance!')	
	}


	static getInstance(){
		if(!Singleton[_SINGLETON_]) Singleton[_SINGLETON_] = new Singleton();
		return Singleton[_SINGLETON_]
	}
}

export default Singleton